We speak as if we have ideas, but I would deny that there were in fact any ideas located in some actual place; indeed, I would argue against the existence of ideas and would instead simply hold the view that we have brain functions. That we in fact speak as if we literally have ideas located somewhere doesn't mean we in fact have ideas. We do, but I would deny that we do under the narrow (and incorrect) understanding of what it means to say of something that it exists.
We're creative. Not only do we claim that we have a mind, but we claim that we have ideas. We even say that ideas are located in the mind, but under the narrow understanding, we neither have minds or ideas, let alone ideas that are located somewhere--especially not located inside something else that doesn't exist.
Of course, we do have ideas, yet it's only partly because of brain function. What's else is required is a broader understanding of what it means to say of something that it exist; additionally, we have to have a very clear understanding of what constitutes a property, since to say of something that it exists is to say of something that it has properties.
Brain function (as I've said elsewhere) gives rise to the mind. It's not the mind itself. It's something we say that exists--but not because it's physically located somewhere. It's an abstraction--not to be confused with an abstract object. There is a physical basis for our ability to have conceptualizations, but just as we shouldn't confuse our brain function with having a mind, neither should we confuse that which gives rise with that which has risen.
We cannot open the brain and find an idea. We can perhaps find the physical basis for it, but we shouldn't in our failure to locate a specific concept decide that the basis for it is therefore it itself. It's engrained in our use of language to speak as if there are mental objects, but a mental object is no more an actual object anymore than an abstract object is an actual kind of object. Not grasping this is precisely why so many people are prone to deny the existence of abstract objects.
Language can be misleading. A toy car is not a kind of car. It's a kind of toy. The point is that we should be careful not to make assumptions because of word placement. For instance, a mental object is not literally an object. Under the narrow understanding of existence, I would deny that there are mental objects at all. They do exist, just as the mind exists, and there is a physical basis for saying they do--brain function, but brain function alone is insufficient for their existence--as there is something else needed to cross the gap--the gap between that which is physical (what gives rise) and that which is not physical (that which arises)--mental objects, for instance. What is needed and what makes what I'm saying true is deeply tied to language usage.
Scientific progress in the area of brain function is (I'm sure) a wonderful thing, but how and why we are able to have abstract ideas is one thing, but the nature of words used to refer to mental objects as used in our lexicon must be taken into consideration.
And they got the grandfather claws going for them, so you gotta sorta play nice. But not too nice... because then nobody will learn.